Gastric blood flow, mast cell degranulation and micromorphology of gastric mucosa following experimental haemorrhagic shock in dogs.

Ischaemia of the gastric mucosa in haemorrhagic shock appears to be one of the principal factors underlying acute bleeding from the upper gastrointestinal tract. In the present experimental study on dogs the changes of blood flow in the upper gastrointestinal tract were recorded by direct flow measurement in the pertinent vessels. Fourteen mongrel dogs were subjected to haemorrhagic shock lasting for 3 and 4 h. A decline of 46 per cent cardiac output was observed while coeliac artery blood flow decreased by 40 per cent and gastric artery blood flow by 60 per cent. All stages of stress ulcers were documented by light and electron microscopy. In addition, pronounced degranulation of mast cells preceding major tissue damage was observed. In the light of these findings a cascade of events is thought to be present resulting in the development of stress ulcer.